1. The Field of the Invention
The present invention relates to hemostatic compositions and methods for their use in dental procedures. More particularly, the present invention is directed to an improved hemostatic dental composition that can be applied to the gingival area of a tooth.
2. The Related Technology
The development of modern instrumentation and materials, together with increased public awareness of the desirability of tooth preservation, have made cast restorations vital and frequently used elements in restorative and reconstructive prosthodontics dentistry. For years dentists have relied on indirect cast restorations such as crowns to maximize function, integrity, and aesthetics for compromised teeth. A primary concern during cast restoration procedures is the controlling of oral bleeding while taking impressions of teeth for reconstruction. During dental reconstruction or preparation of dental crowns, it is common for dentists to cut gingival or gum tissue in order to fully expose the tooth prior to taking an impression of the tooth. It is imperative that the area surrounding the tooth be clean and dry for an accurate impression to be made. To this end, various astringent or hemostatic agents have been used to stop bleeding.
Most failures of cast restorations can be ascribed to poor marginal fit. A primary reason for poor marginal fit is incomplete reproduction of marginal detail in the impression. That defect, in turn, usually may be attributed to poor tissue management. Poor tissue management is the weak link in fixed prosthodontics. Dentists are continually presented with improved techniques and materials that are dependent upon predictable tissue management for successful results. Tissue management during impression making has traditionally centered on chemical and mechanical means of controlling bleeding plus creating a horizontal and vertical space for the impression material. Controlling tissues is the most important step towards the attainment of a precise fitting for subgingival margins.
Many materials and devices have been proposed for horizontal and vertical retraction of soft tissue and hemorrhage control. Unfortunately, undesirable systemic and local side effects are caused by some of the most effective materials. Such side effects have produced frustration for the dentist and discomfort for the patient.
With the increase of near gingival and/or subgingival bonded restorations, there has arisen an intense need to obtain highly effective sulcular fluid control prior to starting the bonding procedure. Modem adhesive dentistry allows dentists to intimately bond porcelain crowns, inlays, veneers and other materials directly to enamel and dentin. Needless to say, extraneous oral fluids preclude success whether for impression making or adhesive dentistry. Complete tissue and sulcular fluid control must occur prior to enamel and dentin bonding procedures when bonding near or under sulcular tissues.
Various hemostats and astringents have been used in dental procedures to control bleeding and aid in retraction of tissue. One of the most common hemostatic and retraction agents used in dentistry is an aqueous solution of aluminum chloride, marketed under a variety of tradenames by several manufacturers. Ferric salts have also been used as astringents, such as ferric subsulfate (Monsel's solution), ferric sulfate, and ferric chloride. A ferric sulfate solution is disclosed in U.S. Pat. No. 4,551,100, for use in the gingival area as a hemostatic agent having both coagulant and astringent properties. The solution was prepared from aqueous ferric sulfate having a concentration of about 6 to 20% in water and glycol. An astringent gel is disclosed in U.S. Pat. No. 4,617,950, which includes an astringent salt and a bodying agent such as carboxypolymethylene.
In order to apply a prosthetic dental device such as a crown to a tooth, the enamel covering the dentin of the tooth must be cut in order to prepare a surface for application of the crown. Typically, a diamond bur is used on a dental drill that rotates at high speed to enable a dentist to cut by grinding the tooth. A newly cut tooth has a smear layer on the surface of the dentin, which is the semi-attached, semi-fractured residue from cutting the tooth, and includes a semi-attached layer of collagen fibrils. Part of the smear layer enters the dentinal tubules, which open at the surface of the dentin, and forms plugs that occlude the tubules. The smear layer plugs in the dentinal tubules can act as a barrier which can prevent contaminants from entering the tubules and infecting the tooth.
A problem that has been encountered in performing the procedures required for dental restorations has been that the smear layer plugs can be opened up in the dentinal tubules by liquid astringents used to stop bleeding in the gingival area. An astringent or hemostat is typically introduced into the sulcus of a tooth to stop bleeding, but can flow over the top of a tooth and contact exposed dentin. If the astringent or hemostat is too harsh or acidic, it can dissolve the smear layer plugs in the dentinal tubules, allowing harmful contaminants such as bacteria to enter the tooth. The acidic and/or other inherent chemical nature of the astringents has also caused a caustic and unpleasant taste in a patient's mouth during treatments.